Abstract: GIS data is digital content that requires high initial production cost and it is transformed into different digital content according to its usage or access level. The convenience of digital content has increased the demands of the content, but because of characteristic of digital content which can be duplicated unlimitedly, the issues on security and copyright have been raised frequently. This paper proposes multi-level access control using Delta Compress Algorithm and by granting access control based on usages and permissions of content, it prevents the illegal use of GIS data which will protect and maintain digital contents consistently. Multi-Level Access Control using Delta Compress proposed in this paper is applied to all digital content in the same way and the same application is possible to Raster Image without additional work for file format.

The development of the Internet and network has enabled real-time services that provide a huge amount of high quality digital content [1]. As digital technology and communication technology are becoming more common, end users can create, modify and distribute digital content with little effort.

The convenience of digital content has increased the demands of the content, but because of characteristic of digital content which can be duplicated unlimitedly, the issues on security and copyright[2][12] have been raised frequently. Especially, GIS data has been extended to Geo-Contents concept which includes digital contents related to geographic information and it is expanded into many different forms of data. [9]-[11]

Copyright protection is needed because of the high initial production cost and importance of the information. Due to the nature of security in GIS data (classified into closed, open, and restricted), access to GIS data is different based on its usage and access level.

This paper proposes a Multi-level access control technique to protect the copyright of Geo-Content which provides in various forms and to control the access of Geo-Content based on access level. When Multi-Level Access Control has accesses and uses Geo-Content, it provides access to Geo-Content that corresponds to its access level. Multi-Level Access Control technique using Delta Compress Algorithm is also easily applied to GIS data that is provided in various forms. In particularly, it can be applicable to Vector data and Raster data as well as file formats which do not have layer and object.